Is sourdough good for diabetes?

When you’re trying to manage blood glucose, the first thing most people cut out is bread.

But bread doesn’t always have to be off-limits. The kind of bread you choose, and how it’s made can make a big difference to how your body responds.

And that’s where sourdough comes in, loved for its chewy texture and tangy flavour, and often praised as a “healthier” choice.

But does its good reputation hold up when it comes to blood sugar and diabetes? Let’s find out.

Overview

What makes Sourdough Different?

Is Sourdough good for Diabetes?

How to choose a good Sourdough

How does Sourdough compare to other breads

What is the best bread for diabetes?

What Makes Sourdough Different?

• Delicious: With its chewy crumb, tangy aroma, and crisp crust, it offers a flavour and texture that’s hard to match. 

• Natural fermentation: Sourdough is made with a starter: a live culture of wild yeasts and lactic acid bacteria (LAB) - instead of commercial yeast.

• Slow fermentation process: The dough ferments for many hours, allowing natural microbes to break down carbohydrates and gluten differently than in standard bread.

• Formation of resistant starch:This process increases resistant starch, a form of starch that your body digests slowly, acting more like fibre and helping steady blood sugar.

• Production of organic acids: Lactic and acetic acids develop during fermentation, which delay stomach emptying and slow the conversion of starch into sugar.

• Gentler blood sugar response: Together, these effects mean carbohydrates from sourdough are released into the bloodstream more gradually, leading to smaller, steadier blood sugar and insulin spikes compared to regular white or yeasted breads.

Is Sourdough Good for Diabetes?

Multiple studies and reviews show that sourdough, especially when made with whole grains, has a lower glycemic impact than regular bread. Key findings include:

• Lower post-meal blood glucose and insulin spikes compared to white or industrially fermented breads.

• Increased resistant starch and organic acid content, which slow carbohydrate digestion.

• Potential improvements in insulin sensitivity

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How to Choose a Good Sourdough

For the best blood sugar benefits, choose:

• Whole-grain or high-fibre flour (wheat, rye, spelt, or barley)

• No added sugar or refined white flour

• Long fermentation traditional sourdough, not quick-rise

• Simple ingredient list: flour, water, salt, starter

How does Sourdough compare to other Breads?

Not all breads affect blood sugar in the same way.

Here’s what the evidence shows from best option to least favourable option. 

• Best: Wholegrain, seeded, or multigrain breads (especially with rye or barley): Usually the lowest glycemic index (GI) and Highest in fibre, keeps you fuller for longer and support steadier blood sugar.

• Wholegrain sourdough breads: The slow fermentation process forms resistant starch and organic acids that reduce glucose spikes.

• Dense rye or barley breads: Naturally low GI and rich in soluble fibre. Shown to improve insulin response and sensation of fullness. 

• Wholemeal or standard wheat breads: Better than white bread but still moderately high GI if finely milled. Choose coarse or stone-ground versions for slower digestion.

• Least favourable: White and standard gluten-free breads: Made from refined starches that digest quickly and spike blood sugar. Offer the least nutritional benefit for glucose control.

What is the best bread for diabetes?

The ideal bread for glucose control combines:

• Whole grains (rye, barley, oats, multigrain) -“Whole grain” should be first on the list.

• High fibre (beta-glucans or resistant starch) - Check fibre content – 3–5 g per slice is ideal.

• Slow fermentation (sourdough process)

• Minimal processing and refined flour - make sure no added sugar. 

What is the best choice for you? 

When it comes to blood sugar management, and especially when you’re also balancing other goals like weight loss, gut health, or kidney support, there’s no single “perfect” bread or diet for everyone.

Your ideal choice depends on your health conditions, preferences, lifestyle, and lab results. What works beautifully for one person can look very different for someone else.

• If you’re living with both type 2 diabetes and kidney disease:
  Choose a sourdough bread made from whole grains with minimal added salt.

• If you have diabetes and are looking to lose weight: 
  Go for whole-grain, seeded, or multigrain breads rich in fiber and protein.

• If you also have high blood pressure:
  Pick low-sodium, whole-grain sourdough or unsalted rye bread. Avoid packaged “artisan” breads that often contain hidden salt.

• If you have gluten sensitivity (not celiac):
  Try sourdough spelt or rye sourdough fermentation can reduce gluten levels and make these easier to digest.

• If gut health is your focus:
  Opt for true sourdough made with a live starter. The natural fermentation supports a healthier gut microbiome and can improve digestion.

  If you’d like help finding what works best for you, I offer personalised nutrition support to help you build confidence with food choices that fit your body and your goals- without restriction or confusion.